Many people carry mobile devices such as smartphones and tablets and interact with these devices frequently. Security-conscious users often lock their device with a passcode that must be entered before the device can be used. When entering device unlock codes in public spaces, such as on public transportation or in a crowd, it is not difficult for a bystander to observe a user's passcode. There is a similar problem when people enter passcodes at an automated teller machine (ATM). Usually, a user at an ATM will enter the passcode with one hand and use the other hand to block line of sight to the keypad, preventing bystanders from learning the user's passcode. However, this method is awkward with a mobile device, where typically a user will need to hold the device with one hand, especially when a user is in public and has nowhere to put the device down.
With traditional systems for authentication, users have limited options. A user may put their phone inside a bag or a backpack to reduce visibility to bystanders, but this method reduces visibility for the user, as well as being inconvenient and potentially drawing unwanted attention from bystanders. A user may also choose to wait to authenticate to their device until there are no bystanders, but this may be impractical for many situations. Accordingly, the instant disclosure identifies and addresses a need for additional and improved systems and methods for authenticating users on touchscreen devices.